Breast pump



FIG. 1 is a perspective view of front, bottom and right side of a breast pump showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines are included for the purpose of illustrating portions of the breast pump which form no part of the claimed design. 

CLAIM The ornamental design for a breast pump, as shown and described. 